Chrysler RG Voyager. Manual — part 350
1.0
INTRODUCTION
The procedures contained in this manual include
all the specifications, instructions, and graphics
needed to diagnose the Mark 20e and Mark 25e
Antilock Braking Systems (ABS). The diagnostics
in this manual are based on the failure condition or
symptom being present at time of diagnosis.
Please follow the recommendations below when
choosing your diagnostic path.
1. First make sure the DRBIII
t is communicating
with the Controller Antilock Brake (CAB) or
Anti-Lock Brake Module (ABM). If the DRBIII
t
displays a “No Response” condition, you must
diagnose that first.
2. Read and record DTC’s (diagnostic trouble codes)
and Freeze Frame information with the DRBIII
t.
3. If no DTC’s are present, identify the customer
complaint.
4. Once the DTC or customer complaint is identi-
fied, locate the matching test in the Table of
Contents and begin to diagnose the symptom.
All component location views are in Section 8.0.
All connector pinouts are in Section 9.0. All sche-
matics are in Section 10.0.
An asterisk (*) placed before the symptom de-
scription indicates a concern with no associated
DTC.
When repairs are required, refer to the appropri-
ate service manual for the proper removal and
repair procedure.
Diagnostic procedures change every year. New
diagnostic systems may be added; carry over sys-
tems may be enhanced. READ THIS MANUAL
BEFORE TRYING TO DIAGNOSE A VEHICLE
CODE. It is recommended that you review the
entire manual to become familiar with all new and
changed diagnostic procedures.
After using this book, if you have any comments
or recommendations, please fill out the form at the
back of the book and mail it back to us.
1.1
SYSTEM COVERAGE
This diagnostic procedure manual covers the
Teves Mark 20e and 25e Antilock Braking System
(ABS) found on the 2005 (RS) Town and Country,
Caravan, and Voyager.
1.2
SIX-STEP TROUBLESHOOTING
PROCEDURE
Diagnosis of the CAB or ABM is done in six basic
steps:
•
verification of complaint
•
verification of any related symptoms
•
symptom analysis
•
problem isolation
•
repair of isolated problem
•
verification of proper operation
2.0
IDENTIFICATION OF
SYSTEM
Vehicles equipped with the Teves Mark 25e an-
tilock brake system can be identified by the pres-
ence of the antilock brake module with a 47-way
connector. Mark 20e has a 24-way connector.
The presence of the Traction Control system is
indicated by the switch and bulb check.
3.0
SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION
3.1
TEVES MARK 20e/25e SYSTEM
DESCRIPTION
The CAB or ABM is used to monitor wheel speeds
and to modulate (control) hydraulic pressure in each
brake channel. The modulated hydraulic pressure is
used to prevent wheel lock-up during braking.
The Teves Mark 20e/25e system uses a diagonal
split hydraulic brake system. In the standard brake
mode the master cylinder primary circuit supplies
pressure to the right front and left rear wheel
brakes, and the secondary master cylinder circuit
supplies pressure to the left front and right rear
wheel brakes.
All vehicles equipped with ABS use Electronic
Variable Brake Proportioning (EVPB) to balance
front-to-rear braking when brakes are applied in
the partial braking range.
3.2
TRACTION CONTROL SYSTEM (TCS)
DESCRIPTION (IF EQUIPPED)
The main purpose of traction control is to reduce
wheel slip and maintain traction at the driven
wheels when road surfaces are slippery. The traction
control system reduces wheel slip by braking the
wheel that is losing traction. The system is designed
to operate at speeds below 56 km/h (35 mph).
3.3
SYSTEM COMPONENTS
ABS
•
anti-lock brake module (ABM)
•
controller antilock brake (CAB)
•
vacuum booster
1
GENERAL INFORMATION
•
master cylinder
•
integrated hydraulic control unit (HCU), 1 pump
motor.
•
4 wheel speed sensor/tone wheel assemblies
•
ABS warning indicator
•
fuses and wiring harness
•
fluid reservoir
•
brake lamp switch
ABS With Traction Control
•
CAB/ABM with Traction Control programming
•
HCU with four additional control valves.
•
TCS Switch
•
TCS Indicator
3.3.1
ABS AND BRAKE WARNING
INDICATORS
The amber ABS warning indicator is located in
the instrument cluster. It is used to inform the
driver that the antilock function has been turned
off. The ABS warning indicator is controlled by the
CAB/ABM. The CAB/ABM controls the lamp with a
command over the PCI bus.
The ABS Warning Indicator will remain lit during
every key cycle until a circuit or component fault is
repaired and the CAB/ABM no longer detects the
fault. After repair of a sensor signal fault or a pump
motor fault, the CAB/ABM must sense all four
wheels at 25 km/h (15 mph) before it will extinguish
the ABS and TCS Indicator.
The Instrument Cluster will illuminate the ABS
Warning Indicator if it loses communication with
the CAB/ABM.
The red BRAKE warning indicator is also located
in the instrument cluster. It can be activated in
several ways. Application of the parking brake or a
low fluid signal from the fluid level switch located in
the master cylinder reservoir will cause the indica-
tor to come on.
3.3.2
CONTROLLER ANTILOCK
BRAKE/ANTI-LOCK BRAKE MODULE
The CAB/ABM is a microprocessor-based device
that monitors wheel speeds and controls the an-
tilock functions. The CAB/ABM contains two micro-
processors that receive identical sensor signals and
then independently process the information. The
results are then compared to make sure that they
agree. Otherwise, the CAB/ABM will turn off the
antilock and turn on the ABS amber warning indi-
cator.
The primary functions of the CAB/ABM are to:
•
detect wheel locking tendencies
•
control fluid pressure modulation to the brakes
during antilock stop
•
monitor the system for proper operation
•
manage traction control functions
•
provide communication to the DRBIII
t while in
diagnostic mode
•
store diagnostic information in non-volatile mem-
ory
The CAB/ABM continuously monitors the speed
of each wheel. When a wheel locking tendency is
detected, the CAB/ABM will command the appro-
priate valve to modulate brake fluid pressure in its
hydraulic unit. Brake pedal position is maintained
during an antilock stop by being a closed system.
The CAB/ABM continues to control pressure in
individual hydraulic circuits until a wheel locking
tendency is no longer present. The CAB/ABM turns
on the pump motor during an antilock stop.
The antilock brake system is constantly moni-
tored by the CAB/ABM for proper operation. If the
CAB/ABM detects a system malfunction, it can
disable the antilock system and turn on the ABS
warning indicator. If the antilock function is dis-
abled, the system will revert to standard base brake
system operation.
The CAB/ABM inputs include the following:
•
diagnostic communication
•
four wheel speed sensors
•
three power feeds: valve, pump, and microproces-
sor
•
brake lamp switch
•
traction control switch
The CAB/ABM outputs include the following:
•
ABS warning indicator actuation
•
12 volts supply to wheel speed sensors
•
valve actuation
•
diagnostic communication
•
PCI bus communication
•
traction control lamp illumination
3.3.3
HYDRAULIC CONTROL UNIT
The hydraulic control unit (HCU) contains the
valve block assembly, and pump/motor assembly.
The HCU is attached to the CAB/ABM.
Valve Block Assembly: The valve block assem-
bly contains valves with four inlet valves and four
outlet valves. The inlet valves are spring-loaded in
the open position and the outlet valves are spring
loaded in the closed position. During an antilock
stop, these valves are cycled to maintain the proper
slip ratio for each wheel. If a wheel detects slip, the
inlet valve is closed to prevent and further pressure
increase. Then the outlet valve is opened to release
the pressure to the accumulators until the wheel is
2
GENERAL INFORMATION
no longer slipping. Once the wheel is no longer
slipping, the outlet valve is closed and the inlet
valve is opened to reapply pressure. If the wheel is
decelerating
within
its
predetermined
limits
(proper slip ratio), the inlet valve will close to hold
the pressure constant. On vehicles which are
equipped with a traction control system, there are
four additional valves, two isolate the master cylin-
der and two shuttle. During a traction control event
the brakes are applied to reduce wheel slippage.
Pump Motor Assembly: The pump motor as-
sembly provides the extra amount of fluid needed
during antilock braking. The pump is supplied fluid
that is released to the accumulators when the outlet
valve is opened during an antilock stop. The pump
is also used to drain the accumulator circuits after
the antilock stop is complete. The pump is operated
by an integral electric motor. This motor is con-
trolled by the CAB/ABM. The CAB/ABM may turn
on the pump motor when an antilock stop is de-
tected. The pump continues to run during the
antilock stop and is turned off after the stop is
complete. Under some conditions, the pump motor
will run to drain the accumulators during the next
drive off. The CAB/ABM monitors the pump motor
operation internally.
3.3.4
ABS SWITCHES/SENSORS
Master Cylinder: The master cylinder is a stan-
dard tandem compensating port design for ABS and
non ABS systems. Traction control vehicles use a
dual center port master cylinder. For proper trac-
tion control operation the standard master cylinder
must not be used.
A fluid level switch is located in the master
cylinder fluid reservoir. The switch closes when a
low fluid level is detected. The fluid level switch
turns on the brake warning indicator by grounding
the indicator circuit. This switch does not disable
the ABS system.
Wheel Speed Sensors and Tone Wheels: One
active wheel speed sensor (WSS) is located at each
wheel. The sensors use an electronic principle
known as magneto-resistive to help increase perfor-
mance, durability and low speed accuracy. The
sensors convert wheel speed into a small digital
signal. A toothed gear tone wheel serves as the
trigger mechanism for each sensor.
The CAB/ABM sends 12 volts to power an Inte-
grated Circuit (IC) in the sensor. The IC supplies a
constant 7 mA signal to the CAB/ABM. The rela-
tionship of the tooth on the tone wheel to the
permanent magnet in the sensor, signals the IC of
the sensor to toggle a second 7 mA power supply on
or off. The output of the sensor, sent to the CAB/
ABM, is a DC voltage signal with changing voltage
and current levels. The CAB/ABM monitors the
changing amperage (digital signal) from each wheel
speed sensor. The resulting signal is interpreted by
the CAB/ABM as the wheel speed.
Because of internal circuitry, correct wheel
speed sensor function cannot be determined
by a continuity or resistance check through
the sensor.
Correct antilock system operation is dependent
on tone wheel speed signals from the wheel speed
sensors. The vehicle’s wheels and tires should all be
the same size and type to generate accurate signals.
In addition, the tires should be inflated to the
recommended pressure for optimum system opera-
tion. Variation in wheel and tire size or significant
variations in inflation pressure can produce inaccu-
rate wheel speed signals; however, the system will
continue to function when using the correct factory
mini-spare.
3.3.5
ABS INITIALIZATION
System initialization starts when the key is
turned to “run”. At this point, the CAB/ABM per-
forms a complete self-check of all electrical compo-
nents in the antilock systems.
Between 8-17 km/h (5-10 mph), a dynamic test is
performed. This will momentarily cycle the inlet
and outlet valves, check wheel speed sensor cir-
cuitry, and run the pump motor at 25 km/h (15
mph). The CAB/ABM will try to test the pump
motor. If the brake pedal is applied the test will be
run at 40 km/h (24 mph) regardless of brake switch
state. If, during the dynamic test, the brake pedal is
applied, the driver may feel the test through brake
pedal pulsations. This is a normal condition.
If any component exhibits a trouble condition
during system initialization or dynamic check, the
CAB/ABM will illuminate the ABS warning indica-
tor and TCS Indicator, if equipped.
3.3.6
ABS DIAGNOSTIC MODE
To enter diagnostic mode, a vehicle speed must be
below 10 km/h (6 mph) and no ABS condition
present. If vehicle speed is not below 10 km/h
(6 mph), a “No Response” message could be dis-
played by the DRBIII
t. The following are charac-
teristics of diagnostic mode:
– The amber ABS warning indicator will blink
rapidly. If a hard trouble code, such as Battery
Voltage Out of Range code is present, the
indicator will be illuminated without blinking
until the trouble condition is cleared.
– Antilock operation is disabled.
– The HCU valves cannot be actuated when the
vehicle speed is above 8 km/h (5 mph). If valve
actuation is attempted above 8 km/h (5 mph), a
“No Response” message will be displayed on
the DRBIII
t.
3
GENERAL INFORMATION
3.3.7
TRACTION CONTROL OPERATION
(IF EQUIPPED)
The CAB/ABM monitors wheel speeds. If, during
acceleration, the module detects front (drive) wheel
slip and the brakes are not applied, the CAB/ABM
will enter traction control mode. Traction control
works in the following order when drive wheel slip
is detected.
1. Close the (normally open) isolation valves.
2. Start pump/motor and supply volume/pressure
to front hydraulic circuits (pump runs continu-
ously during traction control).
3. Open and close build and decay valves to main-
tain minimum wheel slip and maximum trac-
tion.
The cycling of the build and decay valves is
similar to the ABS except that they work to control
wheel spin by applying brakes. ABS function is to
control wheel skid by releasing brakes.
Two pressure relief valves allow excess fluid vol-
ume to return to the reservoir when not used by the
build/decay cycles. These are required because the
pump supplies more volume than the traction con-
trol system requires.
If at any time the brake pedal is applied during a
traction control cycle, the brake lamp switch will
trigger the CAB/ABM to switch off the traction
control.
The traction control system will be enabled at
each ignition cycle. It may be turned off by depress-
ing the Traction Control Switch. The traction con-
trol system function lamp will illuminate Traction
Control immediately upon depressing the traction
control switch button. The indicator will illuminate
during a traction control event.
If the CAB/ABM calculates that the brake tem-
peratures are high, the traction control system will
become inoperative until a time-out period has
elapsed. When in this thermal protection mode, the
traction control indicator will illuminate; however,
a fault will not be registered.
3.4
DIAGNOSTIC TROUBLE CODES
The CAB/ABM may report any of several Diag-
nostic Trouble Codes (DTC)s. For a list of the DTC’s
diagnosed in this manual, refer to the Table of
Contents.
3.5
FREEZE FRAME
Freeze Frame takes a “snapshot” of specific vehi-
cle information the instant an ABS failure is recog-
nized and stores this information into the CAB/
ABM memory. This information can be accessed
using the DRBIII
t to help diagnose the fault.
Freeze Frame will capture the first time failure or
only a new failure that occurs during the current
ignition cycle.
3.6
DRBIII
T ERROR MESSAGES AND
BLANK SCREEN
Under normal operation, the DRBIII
t will dis-
play one of only two error messages:
– User-Requested
WARM
Boot
or
User-
Requested COLD Boot.
If the DRBIII
t should display any other error
message, record the entire display and call the
STAR Center. This is a sample of such an error
message display:
ver: 2.14
date: 26 Jul93
file: key_itf.cc
date: Jul 26 1993
line: 548
err. 0x1
User-Requested COLD boot
Press MORE to switch between this display
and the application screen.
Press F4 when done noting information.
3.6.1
DRBIII
T DOES NOT POWER UP
If the LED’s do not light or no sound is emitted at
start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage (data link
connector cavity 16). A minimum of 11 volts is
required to adequately power the DRBIII
t.
If all connections are proper and the vehicle
battery is fully charged, an inoperative DRBIII
t
may be the result of faulty cable or vehicle wiring.
3.6.2
DISPLAY IS NOT VISIBLE
Low temperatures will affect the visibility of the
display. Adjust the contrast to compensate for this
condition.
4
GENERAL INFORMATION
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